Crouzet Automatismes

Luc Raffestin

G&eacute;rard Blain

Hybrid power relay used for opening or closing electrical circuits, including an electrical contact having a mechanical movement, a semiconductor component in parallel with the electrical contact, and a control unit which in response to a logic input level causes the electrical contact to close (open) and the semiconductor component to be turned on. The control unit generates a contact-make signal for closing the contact, and a control signal that turn on the semiconductor component for a predetermined period of time. The control signal prevents the semiconductor component from being turned on after the predetermined period if the electrical contact fails to close so that the semiconductor component is undamaged. Also, the control unit generates a contact-break signal for opening the electrical contact, and turning on the semiconductor component before the electrical contact has opened by means of a control signal which terminates at the end of a second predetermined period after the electrical contact has opened.

Hybrid power relay

In order to produce a phase control device which is free of the constraints of drifts due to the supply frequency or to the temperature of the components forming it, a method is recommended in which a command signal delivered by a control is modified by a converter in order that the activity of the actuator controlled by this device is a linear function, in all cases, of a control signal. As an improvement, account is taken of the variation in frequency of the supply signal by multiplying the convertible signal by a measurement of the duration of the period of the power signal.

Method of control by phase angle

In order to implement a method of graduating the dissipation of an alternating electrical power signal, provision is made to place the position (Reg,) of a period of the alternating signal in correspondence with the binary inverse (Reg,) of a digitized set-point parameter. It is shown that, in this way, the periods of dissipation are ideally distributed among the periods of non-dissipation. This has the principal effect of reducing the effects of blinking which are particularly undesirable when the rise time of the phenomenon to be controlled is short as regards the period of the alternating electrical signal.

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Valence, France

Luc Raffestin